Kawasaki BX200L Encoder Issue

    Good Day,


    I have a BX200L tranverse material handling robot. Its less than 2000 hours on the robot, and now it seems to for no found reason and no alarms that we can find and everyone saying they didn't touch the encoder values or changed them. The robot will run several racks and then out of the blue it will just decide to be off by at least 6" to 8", but you can go back and to the reference point reteach the steps and then your fine for a couple weeks it seems and then boom it happens again. So, I ask you is this something you have seen before and know what to do, or should I call a priest?


    Thanks Chad

    Quote from cbrackin77

    and now it seems to for no found reason and no alarms

    There is ALWAYS a reason, or else it wouldn't happen.


    Without ANY details, just what are you asking, if it has been seen before, then yes.

    If you are then asking for an answer, then this is where details are required along with your story.

    If the robot is not showing errors, then it is very likely doing exactly what it is told to do with the configuration, settings, programs and data associated with how it's been setup with.


    1. Why do you think this is an encoder issue when no errors or alarms are being produced.

    2. What is 6 to 8 inches at least off mean.

    3. In what direction is 6 to 8 inches at least.

    4. Does it go from good position to 6 to 8 inches, or does it gradually drift until someone notices.

    5. Is 6 to 8 inches your measurement values or the robots measurement values.

    6. Values would help - ie programmed position values vs actual position values when noticed.

    7. Has the robot suffered ANY form of collision.

    8. Are there any loose bolts ANYWHERE relating to mounting points.

    9. Have you checked all mechanical zeroing for all joints.

    10. Have you tried and identify which joint(s) are causing this 6 to 8 inches.

    11. Have you run a simple test program to try and replicate the problem using joint angles.

    12. Has the external axis been correctly configured.

    13. What programming are you using AS or BLOCK.

    14. What steps are you referring to when you say reteaching steps.

    15. Have you checked whether these steps need reteaching.

    16. Are locations calculated and creating shifts from a reference position.

    17. What about providing some code example of what is being executed.

    18. Have you got any holy water to sprinkle on the application - Just in case you do need to call a priest.

    6" to 8" Y negative.

    The problem has happened before, and has been corrected with reteaching to the settings that the robot was doing without issues.

    I have tried everything to see why it is losing position. I have checked the zero position, I have checked the PIN position. It is a track robot and of course the 7th axis is the robot moving on the track. I have checked the gears, the teeth, I have ran it back and forth a hundred times. I have checked all the logs to see if they had an error, or if someone changed the the points. I have ran backups and compared them.

    And every time it has been taught to the position that it was originally taught, it will be fine for 2-3 weeks and then out of the blue it is off.

    I'm going to back and check the robot over head to toe again. I was just hoping someone had this same episode or similar.


    I appreciate any feedback, Thanks

    Also it does not drift, its fine on several parts, out of the same rack and then it will just be off location. By 6-8" Y-, and as before, no errors, no faults, no cubic-S alarms. Nothing, it just wonders off position.

    Negative Y of what exactly BASE, FRAME or TOOL?

    You say you have compared data values to be correct, so how can you say it is negative Y of anything.

    Quote from cbrackin77

    The problem has happened before, and has been corrected with reteaching to the settings that the robot was doing without issues.

    What does this mean exactly?

    - Re-teaching positions.

    - Re-loading an earlier backup.

    - Zeroing, changing configuration settings.


    There is no 'quick fix' until the source of the problem is correctly identified.

    Some answers to many of my listed points would help me advise you to determine where the problem is.

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